JPH0280434A - Molded resin and production thereof - Google Patents

Abstract

PURPOSE:To obtain easily a molded resin wherein only a required part of the surface has a crosslinked structure by impregnating a required part of a molded thermoplastic resin with an org. peroxide and performing crosslinking treatment by heating it at a temp. where the molded resin is not deformed. CONSTITUTION:A thermoplastic resin (e.g., polyurethane or polyamide resin) is formed into a required shape. Then, a required part of this molded resin is impregnated with an org. peroxide (e.g., dicumyl peroxide). Then, the org. peroxide is decomposed at a temp. where the molded resin is not deformed and the crosslinking treatment of the required part of the molded resin is performed with the generated free radicals. It is thereby possible to prepare a molded resin wherein a thermoplastic state remains on a part to be treated as it is and only the part where various excellent properties such as chem. resistance are required, has a crosslinked structure.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a resin molded article and a method for manufacturing the same, and more particularly to a resin molded article having a crosslinked structure only in desired portions and a method for manufacturing the same.

(Prior Art and its Problems) Conventional resin molded products can be roughly classified into molded products made of thermal RIT Hayabusa bamboo resin and molded products made of thermosetting resin.

Thermoplastic resin moldings are obtained by heating a thermo-M9 resin to make it fluid and shaping it into an arbitrary shape, and then cooling it to fix the shape. Molded products can be manufactured very easily and are currently produced in large quantities.

Therefore, thermoplastic resin molded products are very easy to manufacture and therefore inexpensive, and since they are softened by reheating and cast, they are easy to process after molding, and furthermore, their surfaces are resistant to the effects of solvents. It has many advantages such as easy printing and gluing.

Due to these numerous advantages, for example, polyethylene, polypropylene, polystyrene, AS, ABS, polyester, polyamide, polyurethane, etc. are widely used in general applications.

The disadvantages of thermoplastic resin moldings as described above are the opposite of the above advantages, and since they are thermoplastic resins, they have poor heat resistance,
It is well known that various physical properties such as solvent resistance, abrasion resistance, chemical resistance, and compression resistance are inferior.

Therefore, apart from numerical uses, their use is extremely limited in industrial uses that require various strict performances such as those mentioned above, and special and expensive engineering plastics are used. However, it still does not fully solve the above drawbacks.

On the other hand, thermosetting resin molded products exhibit plasticity during OiT or molding, but the resin develops a three-dimensional crosslinked structure due to heating during molding, and thereafter becomes an insoluble and infusible molded product. Therefore, it solves many of the drawbacks of the above-mentioned thermoplastic resin molded products, and is widely used in industrial fields where various physical properties such as heat resistance, chemical resistance, and compression resistance are required.

Many types of rigid thermosetting resins are known, such as phenolic resins, melamine resins, and epoxy resins, but the drawbacks of molded products made from such thermosetting resins are firstly the molding method. is limited to press molding methods, compression molding methods, etc., and there are many process problems such as curing too early or too slow during molding, making it easier to mold than thermoplastic resin molded products. It is significantly inferior in this respect.

Further, regarding molded products, since the entire molded product is insoluble and infusible, there are disadvantages in that it is almost impossible to process the molded product after molding, and it is difficult to print or adhere to the surface.

Is there a known method to solve the above problems by molding a thermoplastic resin and then irradiating the molded product with electron beams or cobalt gamma rays to give the molded product a cross-linked structure? This method requires very large-scale irradiation equipment and cannot be used for small-scale production.

Therefore, the object of the present invention is to provide a resin molding that can be molded easily like a thermoplastic resin during molding, and that exhibits excellent performance of both thermoplastic resin molded products and thermosetting resin molded products after molding. It is about providing something.

(Means for solving problems) The above objects have been achieved by the present invention as described below.

That is, the present invention consists of two inventions, the first invention is a thermoplastic resin molded product made of a thermoplastic resin and having at least a part of the surface a crosslinked structure, and the second invention is:
It is characterized by infiltrating an organic peroxide into a desired part of a thermoplastic resin molding, decomposing the organic peroxide at a temperature that does not deform the molding, and cross-linking the desired part of the molding with the generated free radicals. This is a method for manufacturing a resin molded article.

(Function) A resin molding is made by first making a resin molding from a thermoplastic resin, and then permeating the organic peroxide into the desired part of the molding, and then heating and cross-linking the molded product, which cross-links only the desired part. things are provided.

(Preferred embodiment h6) Thermoplastic resins used in the present invention include, for example, polyolefin resins such as polyethylene and polypropylene, polystyrene resins, polyvinyl chloride resins, AS,
Any thermoplastic resin such as ABS resin, vinyl acetate resin, polycarbonate resin, acetyl cellulose resin, polyester resin, polyamide resin, polyurethane resin, etc. can be used.

Although these thermoplastic resins generally do not have polymerizable double bonds therein, organic peroxides can be permeated and heated by the method of the present invention even in the absence of polymerizable double bonds. Accordingly, the object of the present invention can be achieved.

Furthermore, in a preferred embodiment of the present invention, when molding a resin molded article from the thermoplastic resin having no polymerizable double bonds as described above, a compound having a polymerizable double bond is mixed therein. In this case, the crosslinking reaction using the organic peroxide can be carried out more effectively.

As the compound having a polymerizable double bond as described above, thermoplastic polymers and oligomers such as unsaturated polyester resins, urethane acrylates, polyester acrylates, and epoxy acrylates can be used.

In the method of the present invention, first, a molded article is molded from a thermoplastic resin. What method do you use for this type of molding?

Any conventionally known method for molding thermoplastic resins can be used. For example, any molding method such as injection molding, extrusion molding, 1'↓air molding, blow molding, foam molding, slush molding, casting, etc. may be used, and conventional thermosetting methods such as compression molding, transfer molding, etc. may be used. A molding method using a synthetic resin may also be used. Of course, the thermoplastic resin used in such arbitrary molding may be a thermoplastic resin that does not have a polymerizable double bond, a thermoplastic resin that has such a polymerizable double bond, or a thermoplastic resin that has a polymerizable double bond. thermoplastic resin mixed with a compound having

Moreover, the shape of molded products made of such thermoplastic resin is not limited at all, and examples include ball joints made by injection molding, various bushings, various dust covers, various shock absorbers, brake stoppers, and O-rings. kind,
Oil supply rings, plate spring spacers, door lock striker-1 various gears, packings, sealing materials, plate materials, pickers, Kl' holders, urethane balls,
Various tied casters, thrust washers, tuner parts, tap water faucets, sole materials for various sports shoes, various lifts, heel tops, ski grip materials, sprockets for snowmobiles, caterpillars, military boots and safety shoes. Shoe sole materials, golf balls, belts, gaskets, plugs, sockets, etc., as well as extrusion molded F...conveyor belts, water containers, brewing containers, flexible containers, motor bending and boiling. Bags, sheets for transporting powder and granular materials, various raincoats, clothing, extruded film products such as various tapes, extruded tube products such as inflation products, various tubes, and various hoses, underground cables, and submarine products. Cables, power/transmission cables, lead wires, computer wiring, automobile wiring,
Examples include coated extrusion products such as various enameled wires, belt extrusion products of various belts, and the like.

In the present invention, an organic peroxide is permeated into the molded article as described above.

The organic peroxides used in the present invention include acetyl cyclohexyl oxide, isobutyl peroxide, diisopropyl peroxide carbonate, di-n-propyl peroxide carbonate, similystyl peroxide carbonate, and di(2-ethoxyethyl) peroxide. Oxide carbonate, 2,4-dichlorobenzoyl peroxide, t-butyl peroxypivalate, 3,5,5-trimethylhexanonyl peroxide, octanoyl peroxide, lauroyl peroxide, acetyl peroxide, m-toluroyl peroxide Examples include organic peroxides such as oxide, benzoyl peroxide, cyclohexanone peroxide, methyl ethyl ketone peroxide, dicumyl peroxide, and cumene hydroperoxide, and any other known organic peroxides may be used in the present invention. I can do it. In addition, in the present invention, the above-mentioned organic peroxides include cobalt, lead, manganese, naphthenic acid and octylic acid.
By using salts such as zinc, iron, calcium, lithium, and chromium in combination, the generation of free radicals and crosslinking reactions can be made more efficient and accelerated.

The portion through which the organic peroxide permeates may be the entire molded product or a portion of the molded product. For example, if the molded product is a hollow molded product such as a hose, the organic peroxide may be infiltrated throughout the product, only in its surface layer, or only in its inner layer. It may be infiltrated into the hose, or it may be infiltrated into only a part of the hose instead of the entire length, and it may be infiltrated into the entire molded product or the heat resistance, chemical resistance, and geothermal curing resin molded product required. It can penetrate only the areas that require performance.

The method of infiltration may be one of immersing part or all of the molded product in the organic peroxide solution as described above, applying these liquids to the molded product, or promoting penetration using pressure. But that's fine.

In particular, when permeating, the organic peroxide solution is heated to a temperature that does not harm the molded product, for example, about 50 to 200 degrees Celsius, thereby promoting the peroxide permeation. I can do it.

The solvent used for permeating the organic peroxide varies depending on the thermoplastic resin used for molding, and a solvent that partially dissolves or swells the thermoplastic resin used for molding is particularly preferred. For example, in the case of polyamide resin, methanol or a mixed solvent of methanol and other solvent is used, in the case of polyurethane resin, 1d solvent of methyl ethyl ketone or methyl ethyl ketone and other solvent is used, and in the case of polyester elastomer, tetrahydrofuran or tetrahydrofuran is used. In the case of mixtures with other solvents and olefin elastomers, square group solvents seem to be suitable.

As described above, the organic peroxide permeates into the desired part of the molded product, but the reaction between the peroxide and the thermoplastic resin or the added polymerizable compound proceeds over a long period of time even at room temperature. Therefore, heating is not an essential condition. However, in numerical terms, (1) the organic peroxide is permeated by heating the molded product at a temperature of about 50 to 200°C to an appropriate temperature for several minutes to several hours without causing deformation. It is preferable to decompose it to generate free radicals and promote the crosslinking reaction.

As described above, a resin molded article can be obtained by the method of the present invention.

(Function) According to the present invention as described above, it is possible to provide a resin molded article that exhibits the excellent physical properties of a thermosetting resin in necessary parts by a general method of molding a thermoplastic resin. .

Therefore, in the method of the present invention, any molding method can be adopted and a molded product of any shape can be obtained.Furthermore, in the resin molded product according to the method of the present invention, the part of the molded product to be processed is in the state of thermoplastic resin. Since parts that require various high physical properties can be left as they are and have a crosslinked structure, it is almost impossible to perform various processing after molding, as with conventional thermosetting resin moldings. One problem has been resolved.

Furthermore, in the resin molded product produced by the method of the present invention, for example, only the surface area that comes into contact with chemicals has a thermosetting crosslinked structure, while the other areas are left as a thermoplastic resin with aging formability. Since the thermosetting part and the thermoplastic resin part are completely integrated, it has excellent flexibility, flexibility, workability, adhesion to other articles, printability, etc., which is sufficient for molded products. It has the advantage of being a molded product with various physical properties. In contrast, in the case of conventional thermoplastic resin moldings or thermosetting resin moldings, such benefits could not be achieved.

(Example) Next, the present invention will be described in more detail with reference to Examples. In addition, in the first sentence, parts or % are 1gl unless otherwise specified.
It is a standard.

Example 1 Adipate thermoplastic polyurethane resin (JISA90
) was used to obtain a roller-shaped molded product by injection molding. This molded product is 1,1-bis(t-butylperoxy)3,3
．． After soaking in a 50% methyl ethyl ketone solution in 5-trimethylcyclohexane for 4 hours, the methyl ethyl ketone was evaporated at room temperature, and the methyl ethyl ketone was then soaked at 120 to 150°C for 2 hours.
A heat treatment was performed for a period of time to cause decomposition of peroxide and cross-linking reaction, thereby obtaining a resin molded article of the present invention. The physical properties of this molded product were compared with those of the same molded product (untreated product) to which the method of the present invention was not applied, and the results were as follows.

Hardness JISA90
Heat resistance to JIS 88 140℃
Heat resistance is the softening point under load, and heat resistance is 2℃/mi with a load of 500g/crn' applied to the bottom of the molded product.
n.

The temperature is expressed as the temperature at which the material suddenly deforms.

Example 2 A pneumatic tubular molded product was obtained by extrusion molding using a polyester elastomer. This molded product was dissolved in a 50/30/20 solution of 3.3.5-trimethylcyclohequinonyl peroxide/tetrahydrofuran/methyl ethyl ketone for 5 minutes.
After being immersed for a period of time, it was taken out, air-dried, and heat treated at 120 to 150° C. for 3 hours to decompose the A oxide and cause a crosslinking reaction, thereby obtaining a resin molded article of the present invention. The physical properties of this molded product and the physical properties of the same molded product to which the method of the present invention was not applied were compared in the same manner as in Example 1, and the results were as follows.
Wear resistance above ℃ 15 or more 7 or less Furthermore, the abrasion resistance is taper method C5-17 (mmg 71000 times)
This is the value at

Example 3 Polyethylene, polyamide, polycarbonate, or polyvinyl chloride was used as the thermoplastic resin, tert-butylperoxy-3,5,54-limethylhexanoate was used as the batter compound, and the others were real hb Examples 1 and 2
A molded product with similarly improved physical properties was obtained in the same manner as above.

Claims (4)

[Claims] (1) A thermoplastic resin molded article made of a thermoplastic resin and having at least a portion of its surface a crosslinked structure. (2) The organic peroxide is infiltrated into the desired part of the thermoplastic resin molded product, the organic peroxide is decomposed at a temperature that does not deform the molded product, and the desired part of the molded product is cross-linked using the generated free radicals. A method for producing a resin molded article, characterized by: (3) Claim 2 in which the thermoplastic resin has a polymerizable double bond
The manufacturing method described in. (4) The manufacturing method according to claim 2, wherein the thermoplastic resin contains a compound having a polymerizable double bond.